Open end spinning apparatus

ABSTRACT

An open end spinning apparatus comprises a hollow spinning rotor which is open at its upper end and closed at its lower end and which has an inner surface free from apertures and concentric with respect to the rotary axis of the rotor, said inner surface of the rotor having a rotor wall portion which extends from the open upper end of the rotor radially outwardly with respect to the rotor axis and downwardly to a region of maximum diameter at which region there is formed a localized fibre collecting circumferential groove, the diameter of the groove when measured from the base of the groove in a plane at right angles to the rotary axis of the rotor being at least eleven times greater than the height or mean height of said open upper end above the base of the fibre collecting groove when measured parallel to the axis of the spinning rotor. The lower end or base portion of the rotor may lie in a plane at right angles to the rotor axis or partly in such a plane and partly in a frusto-conical plane. The fibre collecting groove may lie above or below said base portion and may be of any of several radial sections.

United States Patent Croasdale et a1.

[75 Inventors:

OPEN END SPINNING APPARATUS Fred Croasdale, Whalley; Raymond Victor Evans, Blackburn, both of England [73] Assignee: Platt International Limited, Oldham,

England y l. [22] Filed: Jan. 12, 1973 [21] Appl. No.: 322,980

[30] Foreign Application Priority Data 1 Jan. 14, 1972 GreatBritain 1903/72 [52] US. Cl. 57/58.89 [51] Int. Cl D0lh 1/12 [58] Field of Search 57/5889, 58.91, 58.93,

[56] References Cited UNITED STATES PATENTS 3,440,812 4/1969 Stary et al...., .l 57/5889 3,481,130 12/1969 Kubovy et all.. 57/5889 3,520,122 7/1970 Shepherd 57/5889 3,540,201 11/1970 Susami et al 57/5895 X 3,640,061 2/1972 Landwehrkamp 57/5889 1 3,650,104 3/1972 Shepherd et a1 57/5891 3,651,632 3/1972 Shepherd 57/5895 3,696,604 Nozaki et a1 57/5895 Primary Examiner-John Petrakes 57 ABSTRACT An open end spinning apparatus comprises a hollow spinning rotor which is open at its upper end and closed at its lower end and which has an inner surface free from apertures and concentric with respect to the rotary axis of the rotor, said inner surface of the rotor having a rotor wall portion which extends from the open upper end of the rotor radially outwardly with respect to the rotor axis and downwardly to a region of maximum diameter at which region there is formed a localized fibre collecting circumferential groove, the diameter of the groove when measured from the base of the groove in a plane at right angles to the rotary axis of the rotor being at least eleven times greater than the height or mean height of said open upper .end

above the base of the fibre collecting groove when measured parallel to the axis of the spinning rotor.

The lower end or base portion of the rotor may lie in a plane at right angles to the rotor axis or partly in such a plane and partly in a frusto-conical plane. The fibre collecting groove may lie above or below said base portionand may be of any of several radial sections.-

l 12 Claims, 7 Drawing Figures PAIENIEDJUL 91m 3822.541

sum 2 or 2 OPEN END SPINNING APPARATUS The present invention relates to open-end spinning of textile yarns and more particularly to spinning rotors employed with apparatus for the open-end spinning of textile yarns.

In one type of open-end spinning apparatus which has hitherto been proposed, fibres in discrete form are fed in an airstream into a rotating spinning rotor and deposited on an inner surface of the rotor, from which they are picked off by a tail end of yarn which is cominuous ly withdrawn from the rotor.

The rotors employed with the aforementioned type of open-end spinning apparatus are provided with an inner wall surface which extends from the rim of an open end of the rotor radially outwardly from the rotary axis and downwards to a region of maximum diamits lower end and which has an inner surface free from eter, where a fibre collecting surface is formed on to which the fibres are deposited. The distance between the rotor rim and the fibre collecting surface has hitherto been quite substantial in order to ensure that fibres entering the rotor contact the wall surface and slide to the fibre collecting surface and are not swept to waste by the airstream passing out of the open end of the rotor.

It has, however, been found that when spinning with such rotors dust and debris tend to accumulate on an upper region of the inner wall surface above the fibre collecting surface. This accumulation of dust and debris is eventually dislodged from the wall surface and, because of its high mass, is not carried-out of the rotor by the air flow, but moves toward and settles on the fibre collecting surface. Such an occurrence adversely affects the spinning operation by ultimately causing a yarn breakage.

Rotors for the aforementioned type of open-end spinning apparatus have also been provided with apertures either at or below the fibre collecting surface in order to create an airstream in which the fibres are transported into the rotor and to exhaust air from within the rotor. The problem of dust end debris deposition on the inner wall surface is not so acute with such rotors since dust and debris are removed from the rotor through the apertures. However, the presence of apertures poses problems from a technological aspect in that the direction'of the airflow is not consistent with optimum spinning conditions. Furthermore, it has been found that the apertures tend to become blocked and this disadvantage seriously affects spinning performance and the rotor requires constant maintenance.

In addition to the aforementioned disadvantages it has been found that the aforementioned rotors are unsuitable for operating at high speeds. A rotor whose rim is a substantial height above the fibre collecting surface results in large internal and external surface areas which produce a high air drag, and a large amount of power is required to rotate it particularly at high speeds. Also these rotors have a high moment of inertia and this is disadvantageous in so far that a large amount of power is needed to accelerate the rotor to high speeds and also to decelerate the rotor from these high speeds down to rest. Furthermore, a large mass rotor is unsatisfactory, since it acts outside the bearing system in which the rotor spindle is supported and this results in a spindle having a lower critical speed of whirl. Rotors provided with'apertures in the'roto'r wall have the apertures and concentric with respect to the rotary axis of the rotor, said inner surface of the rotor having a rotor wall portion which extends from the open upper end of the rotor radially outwardly with respect. to the rotor axis and downwardly to a region of maximum diameter at which region there is formed a localised fibre collecting circumferential groove, the diameter of the groove when measured from the base of the groove in a plane at right angles to the rotary axis of the rotor being at least seven times greater than the height or mean height of said open end above the base of the fibre collecting groove when measured parallel to the axis of the spinning rotor.

Preferably, said diameter of the groove is in the region of 11, 13 or 16 times the said height or mean height of said open end above the base of the fibre collecting groove.

The said inner surface of the rotor preferably includes a rotor base portion extending radially or generally radially outwardly from the rotary axis of the rotor to said region of maximum diameter.

Some embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings in which:

FIG. 1 is a cross-section through a spinning unit of open-end spinning apparatus in accordance with a first embodiment of the invention,

FIG. 2 is a cross-section of a portion of the spinning rotor of the unit shown in FIG. 1, drawn to an enlarged scale;

FIG. 3 is a cross-section of a spinning rotor of the same cross-sectional profile as the spinning rotor shown in FIG. 1, but of larger diameter, in accordance with a second embodiment of the invention;

FIGS. 4 & 5 are cross-sections of spinning rotors of spinning units accordance to a third & fourth embodiments of the invention, and

FIGS. 6 and 7 are crosssections of portions of the rotors shown in FIGS. 4 and 5, drawn to enlarged scale S.

Referring to FIG. 1, a spinning rotor 1, which is open at the top and closed at the bottom, is mounted on one end of a driving shaft 2 suitably supported in bearings (not shown). The driving shaft 2 has a portion 3 of reduced diameter which is received by a centrally bored hole 4 in the spinning rotor l. A recess 5 is formed in the bottom of the spinning rotor l to provide a seating for a washer 6. The spinning rotor 1 is connected to the driving shaft 2 by means of a screw 7 passing through the washer 6 and screwed into driving shaft 2. The length of the bored hole 4 is greater than the length of the reduced diameter portion 3 so that tightening of the screw 7 has the effect of clamping the spinning rotor 1 against a shoulder8 on the driving shaft 2.

The spinning rotor 1 is enclosed in a housing 9, which is, in the operation of the unit, connected to a source of suction through a suction duct 10. The housing 9 is provided with a closure member 11 which has a centrally depending cylindrical portion 12 which terminates in the region of the open top of the spinning rotor 1 and preferably slightly below the rotor rim. Mounted in the closure member 11 is a fibre feed duct 13 and a yarn delivery tube 14. The tube 14 is arranged coaxially with the spinning rotor l and terminates within the rotor in the form of a bell-shaped mouth 15. In a throat portion of the mouth a plurality of grooves 16 are provided.

Refering now to FIG. 2, the inner surface of the rotor 1 is formed by a rotor upper wall portion 17 which extends from the open end of the rotor 1 radially outwardly from the rotary axis of the rotor and downwardly to aregion of maximum diameter of the inner surface, a localised fibre collecting circumferential groove 18 located at the region of maximum diameter and a rotor base portion which extends from the rotary axis of the rotor 1 over a region 20 in which it is flatand at right angles to the rotary axis of the rotor and then over a region 21 in which it extends, radially outwardly from the rotary axis of the rotor and upwardly to the region of maximum diameter. As will be seen, the base portion comprising regions 20 and 21 forms a shallow dish-shaped base for the interior of the rotor 1.

The angle between upper wall 19 and lower wall 22 of the groove 18 to 30 and is made'up of an angle of 20 between the upper wall 19 and a horizontal plane together with an angle of between the lower wall 22 and a horizontal plane. Preferably the latter angle does not exceed In operation, fibres in discrete form are transported down the fibre feed tube 13 in an airstream derived from suction applied to the suction duct 10 and are deposited in the V-shaped fibre collecting groove 18 where they are compacted to form a ring of fibres. From the groove 18 the fibres are removed by twisting them into a tail end of a spun yarn which is withdrawn through the delivery tube 14 by delivery means (not shown).

In the rotor shown in FIGS. 1 and 2, the diameter D of the groove 18 when measured from base portion 181 of the groove in a plane at right angles to the rotary axis of the rotor is l 1 times greater than the mean height h of the rim of the open end of the rotor 1 above the base portion 181 when measured parallel to the axis of the rotor 1.

While the height h is kept as small as is practicable and such that fibres are not carried out of the rotor by the airstream, the rotor does not suffer from the disadvantage encountered with formerly known rotors of dust and debris collecting on the rotor wall portion 17 of the inner surface. Preferably, the diameter D of the groove 18 measured from the base 181 of the groove is at least seven times the aforementioned height h and it has been found that a spinning rotor having a ratio of diameter D to height h in the region of l l 1 is particularly suitable for performing at high rotor speeds in short staple yarns.

The flat region of the rotor base portion lies, as shown, slightly beneath the base 181 of the fibre collecting groove 18. In FIG. 2,'d represents the distance between the rim of the open end of the rotor and the flat region 20. Preferably, the ratio between the height 4 h of the rotor rim above the base 181 of the fibre collecting groove 18 to the distance d lies in the range 1 to 1 and 1 to 1.6. Preferably, the ratio of height h to distance d is in the region of 1 to 1.4.

The combination of features found in the rotor shown in FIGS. 1 and 2 gives rise to a highly advantageous construction. The load on the drive means can be kept to a minimum, the resultant low moment of inertia reducing the starting torque and therefore the power required to accelerate the rotor to high speeds and to decelerate the rotor from these high speeds to rest. Also, the low mass of the rotor ensures a low overhang weight when the rotor shaft is supported in bearings, which is particularly advantageous when the bearings are of the type employing a gaseous medium.

The rotor illustrated in FIG. 3 is identical to that illustrated in FIGS. 1 and 2 except in so far that the diameter D is 15 times greater than the height h. It has been found that a rotor of these relative dimensions is particularly suitable for use in the open-endspinning of long staple fibres.

The rotor illustrated in FIGS. 4 and 6 are identical to that illustrated in FIGS. 1 and 2 except in so far that the groove 18 of the rotor shown in FIGS. 1 and 2 is replaced by a groove 23 having parallel upper and lower wall portions 24 and 25 and a base portion 26 which lies in a cylindrical surface coaxial with the axis of the rotor. In addition, the diameter D of the groove 23 when measured from the base portion 26 of the groove in a plane at right angles to the axis of the rotor is thirteen times greater than the mean height of the rim of the open end of the rotor above the base of the fibre collecting groove when measured parallel to the axis of the rotor 1.

In the rotor illustrated in FIGS. 5 and 7, the inner surface of the rotor 1 is formed by a rotor wall portion 17, a localized fibre collecting circumferential groove 28 and a rotor base portion 29. The fibre collecting groove 28 has upper and lower wall portions 30 and 31 which converge to a base portion 32. As will be seen, the upper wall portion 30 of the groove 28 forms a continuation of the rotor wall portion 17, the two portions 17 and 30 lying in the same frusto-conical surface. The

angle between the upper and lower wall portions 30 and 31 of the groove 28 is 30 as in the embodiments described in FIGS. 1 to 3. The base portion 29 of the rotor l is flat throughout its extent and lies in a plane at right angles to the rotary axis of the rotor 1, thereby producing an abrupt change of slope at its junction with the lower wall portion 31 of the groove 28.

In the rotor illustrated in FIGS. 5 and 7, the diameter D of the groove 28 when measured from the base of the groove in a plane at right angles to the rotary axis of of the rotor 1 is seven times greater than the height h of the open end of the rotor above the base 32 of the groove 28 when measured parallel to the axis of the rotor 1. It will, of course, be appreciated that in this embodiment of the invention, the ratio between the height h to the distance a' between the open end of the rotor and the base portion 29 lies in a range below 1 1.

We claim:

1. Open end spinning apparatus comprising a hollow spinning rotor which is open at itsupper end and closed at its lower end and which has an inner surface free from apertures and concentric with respect to the rotary axis of the rotor, said inner surface of the rotor localised fibre collecting circumferential groove, the

diameter of the groove when measured from the base of the groove ina plane at right angles to the rotary axis of the rotor being at least eleven times greater than the height of said open upper end above the base of the fibre collecting groove when measured parallel to the axis of the spinning rotor.

2. Apparatus according to claim 1, wherein the said diameter is in the region of 13 to 16 times the height of said open end above the base of the fibre collecting groove.

3. Apparatus according to claim 2, wherein said groove is formed with a groove base portion, a groove upper wall portion extending to the groove base portion and a groove lower wall portion extending to the groove base portion, wherein the rotor upper wall portion and said groove upper wall portion lie in the same frusto-conical surface and wherein the groove lower wall portion lies in a frusto-conical surface and'extends outwardly and downwardly to the groove base portion.

4. Apparatus according to claim 3, wherein the rotor base portion extends to the groove lower wall portion in a plane at right angles to the axis of the rotor to produce an abrupt change of slope at the junction thereof.

5. Apparatus according to claim 1, wherein said groove is formed with a groove base portion, a groove upper wall portion extending to the groove base portion and a groove lower wall portion extendingto the groove base portion, the groove upper wall portion and the groove lower wall portion converging to the said groove base portion, and the rotor upper wall portion and the groove upper wall portion lying in different frusto-conical surfaces to produce an abrupt change of slope at the junction thereof.

6. Apparatus according to claim 1, wherein said groove is formed with a groove base portion, a groove upper wall portion extending to the groove base portion and 'a groove lower wall portion'extending to the groove base portion, the groove upper wall portion and the groove lower wall portion converging to the said groove base portion, the rotor base portion in the region of said groove and the groove lower wall portion lying in the same frusto-conical surface and the rotor base portion in the region of the rotor axis lying in a plane at right angles to the rotor axis.

7. Apparatus according to claim 1, wherein said groove is formed with a groove base portion, a groove upper wall portion extending to the groove base portion, the groove base portion lying in a cylindrical surface coaxial with the axis of the rotor and the groove upper and lower wall portions lying in spaced planes at right angles to the rotor axis.

8. Apparatus according to claim 1, wherein said groove is formed with a groove base portion, a groove upper wall portion extending to the groove base portion and a groove lower wall portion extending to the groove base portion, the groove upper wall portion and the groove lower wall portion converging to the said groove base portion, and wherein the angle between the groove upper and lower wall portions is 9. Apparatus according to claim 8 wherein the groove upper wall portion is inclined above and the groove lower wall portion is inclined below a plane at i right angles to the rotary axis of the rotor and passing through the groove base portion, and wherein the angle between the groove lower wall portion and said plane 7 does not exceed 15.

10. Apparatus according to claim 9. wherein the angle between the groove lower wall portion and said plane is 10.

11. Open end spinning apparatus comprising a hollow spinning rotor which is open at its upper end and closed at its lower end and which has an inner surface free from apertures and concentric with respect to the rotary axis of the rotor, said inner surface of the rotor having a rotor wall portion which extends from the open upper end of the rotor radially outwardly with respect to the rotor axis and downwardly to a region of maximum diameter at which region there is formed a localized fibre collecting circumferential groove, the diameter of the groove when measured from the base of the groove in a plane at right angles to the rotary axis of the rotor being at least eleven times greater than the height of said open upper end above the base of the fibre collecting groove when measured parallel to the axis of the spinning rotor and the ratio of the maximum distance between said rotor base portion and the said open end when measured parallel to the axis of the rotor to the said height of the open end above the base of the fibre collecting groove being not greater than 1 1.6.

said ratio is l 1.4. 

1. Open end spinning apparatus comprising a hollow spinning rotor which is open at its upper end and closed at its lower end and which has an inner surface free from apertures and concentric with respect to the rotary axis of the rotor, said inner surface of the rotor having a rotor wall portion which extends from the open upper end of the rotor radially outwardly with respect to the rotor axis and downwardly to a region of maximum diameter at which region there is formed a localised fibre collecting circumferential groove, the diameter of the groove when measured from the base of the groove in a plane at right angles to the rotary axis of the rotor being at least eleven times greater thaN the height of said open upper end above the base of the fibre collecting groove when measured parallel to the axis of the spinning rotor.
 2. Apparatus according to claim 1, wherein the said diameter is in the region of 13 to 16 times the height of said open end above the base of the fibre collecting groove.
 3. Apparatus according to claim 2, wherein said groove is formed with a groove base portion, a groove upper wall portion extending to the groove base portion and a groove lower wall portion extending to the groove base portion, wherein the rotor upper wall portion and said groove upper wall portion lie in the same frusto-conical surface and wherein the groove lower wall portion lies in a frusto-conical surface and extends outwardly and downwardly to the groove base portion.
 4. Apparatus according to claim 3, wherein the rotor base portion extends to the groove lower wall portion in a plane at right angles to the axis of the rotor to produce an abrupt change of slope at the junction thereof.
 5. Apparatus according to claim 1, wherein said groove is formed with a groove base portion, a groove upper wall portion extending to the groove base portion and a groove lower wall portion extending to the groove base portion, the groove upper wall portion and the groove lower wall portion converging to the said groove base portion, and the rotor upper wall portion and the groove upper wall portion lying in different frusto-conical surfaces to produce an abrupt change of slope at the junction thereof.
 6. Apparatus according to claim 1, wherein said groove is formed with a groove base portion, a groove upper wall portion extending to the groove base portion and a groove lower wall portion extending to the groove base portion, the groove upper wall portion and the groove lower wall portion converging to the said groove base portion, the rotor base portion in the region of said groove and the groove lower wall portion lying in the same frusto-conical surface and the rotor base portion in the region of the rotor axis lying in a plane at right angles to the rotor axis.
 7. Apparatus according to claim 1, wherein said groove is formed with a groove base portion, a groove upper wall portion extending to the groove base portion, the groove base portion lying in a cylindrical surface coaxial with the axis of the rotor and the groove upper and lower wall portions lying in spaced planes at right angles to the rotor axis.
 8. Apparatus according to claim 1, wherein said groove is formed with a groove base portion, a groove upper wall portion extending to the groove base portion and a groove lower wall portion extending to the groove base portion, the groove upper wall portion and the groove lower wall portion converging to the said groove base portion, and wherein the angle between the groove upper and lower wall portions is 30*.
 9. Apparatus according to claim 8 wherein the groove upper wall portion is inclined above and the groove lower wall portion is inclined below a plane at right angles to the rotary axis of the rotor and passing through the groove base portion, and wherein the angle between the groove lower wall portion and said plane does not exceed 15*.
 10. Apparatus according to claim 9 wherein the angle between the groove lower wall portion and said plane is 10*.
 11. Open end spinning apparatus comprising a hollow spinning rotor which is open at its upper end and closed at its lower end and which has an inner surface free from apertures and concentric with respect to the rotary axis of the rotor, said inner surface of the rotor having a rotor wall portion which extends from the open upper end of the rotor radially outwardly with respect to the rotor axis and downwardly to a region of maximum diameter at which region there is formed a localized fibre collecting circumferential groove, the diameter of the groove when measured from the base of the groove in a plane at right angles to the rotary axis of the rotor being at lEast eleven times greater than the height of said open upper end above the base of the fibre collecting groove when measured parallel to the axis of the spinning rotor and the ratio of the maximum distance between said rotor base portion and the said open end when measured parallel to the axis of the rotor to the said height of the open end above the base of the fibre collecting groove being not greater than 1 : 1.6.
 12. Apparatus according to claim 11, wherein the said ratio is 1 : 1.4. 